The invention relates to apparatus for removing tablets from blister packs of tablets.
Blister packs are a very common means of packaging pharmaceutical tablets and may also be used for packaging swimming pool chemicals, gardening tablets, etc. Such blister packs conventionally include a generally planar member of a plastics material, provided with a series of formations for receiving the tablets. A tablet is inserted into each of the formations, the open ends of which are sealed by means of a backing layer of aluminium foil or other breakable material, which is attached to the plastics material. Each tablet is thus sealed in its own formation until use, when the plastics formation is depressed by finger pressure and the tablet is forced out through the backing layer.
In some establishments, such as large dispensing chemists, there is a need to de-blister large numbers of blister packs of tablets, for example for storage or for making up into individual packs including all a patient""s prescribed tablets. Generally, the mass de-blistering of blister packs in order to remove the tablets is done manually and shop assistants carrying out the de-blistering may damage their fingers and fingernails.
According to the present invention there is provided apparatus for removing tablets from a blister pack including a formation for receiving a tablet and a backing layer which seals the formation and is rupturable to allow removal of the tablet, the apparatus including a flexible adhesive member, means for bringing at least a part of the backing layer of the blister pack into contact with the flexible adhesive member, and means for depressing the formation to rupture the backing layer sealing the formation, when the backing layer sealing the formation is in contact with the flexible adhesive member.
Preferably the blister pack includes a plurality of formations each receiving a respective tablet. Preferably the blister pack includes a substantially planar member from which the formations protrude.
Preferably when the backing layer is bought into contact with the flexible adhesive member, the backing layer adheres to the flexible adhesive member.
Preferably means are further provided for separating the flexible adhesive member in contact with the ruptured backing layer from the associated formation, a part of the ruptured backing layer remaining in contact with the flexible adhesive member and thereby releasing the tablet.
Preferably the flexible adhesive member includes an adhesive coated tape.
The tape may have a thickness of between 0.05 mm and 0.2 mm, and preferably has a thickness of about 0.11 mm. The tape may have a breaking load of between 10 and 30 N/cm and a maximum elongation of between 110% and 130%.
Preferably the tape is a polyvinyl chloride tape.
Preferably the adhesive is a pressure sensitive adhesive. The adhesion of the tape to steel is preferably between 2.5 and 5 N/cm and most preferably about 3.6 N/cm. The adhesion of the tape to itself is preferably about 0.6 N/cm.
Preferably means are provided for conveying the blister pack on the tape between a depressing station where the formation is depressed to rupture the backing layer and a backing layer removal station where a part of the ruptured backing layer is removed from the blister pack.
Preferably the means for conveying the blister pack on the tape includes a tape collector roller which may rotate to draw the tape through the depressing station and the backing layer removal station. The tape collector roller may include a central driven rotatable member which may be between 6 mm and 12 mm in diameter. The tape collector roller preferably further includes an outer substantially cylindrical tape receiving portion which preferably has a diameter of between 60 mm and 120 mm and most preferably about 80 mm. When the central member is rotated, preferably tape is drawn onto and wrapped around the outer tape receiving portion.
Preferably tape for drawing through the depressing station and the backing layer removal station is drawn from a tape cartridge located upstream of the depressing station. The tape cartridge may comprise a roll of tape.
Preferably a carrier plate having a substantially planar upper face is located between the tape cartridge and the depressing station. The carrier plate may receive a blister pack to be de-blistered. Preferably the carrier plate includes a substantially straight edge adjacent the depressing station.
Preferably the tape passes over the carrier plate with its adhesive coated face oriented away from the plate, such that a blister pack located on the carrier plate is received on the adhesive coated face of the tape.
Preferably a guide roller is located above and spaced from the carrier plate. The guide roller may be made of a soft material for lightly pressing the blister pack against the tape. The guide roller may be freely rotatable.
The means for depressing the formation may include means for gripping an edge of the blister pack. These means may include a rotatable driven roller. The driven roller may be located at the depressing station adjacent to and slightly spaced from the edge of the carrier plate. The size of the space between the driven roller and the edge of the carrier plate is preferably adjustable.
Preferably the adhesive coated tape is drawn under the driven roller. Preferably the driven roller draws the blister pack between the roller and the tape. The driven roller may be located about 1 mm from the tape. The driven roller may have a diameter of between 6 mm and 1 mm and preferably has a diameter of about 8 mm.
Preferably as the blister pack is drawn under the driven roller, the driven roller depresses a formation of the blister pack, thereby pushing an enclosed tablet towards the flexible adhesive member and rupturing the backing layer. Preferably the rupture is at the leading edge of a part of the backing layer sealing the formation. Preferably the substantially straight edge of the carrier plate mounts and locates the blister pack during this process.
Preferably the driven roller has a non-stick outer surface.
Preferably the adhesive coated tape passes under the driven roller with its adhesive coated face oriented upwardly.
Preferably a freely rotatable roller is provided downstream of and spaced from the driven roller. Preferably the adhesive coated tape passes over the second freely rotatable roller. The freely rotatable roller is preferably located about 40 mm to 70 mm away from the driven roller. Preferably the driven and freely rotatable rollers are positioned such that the adhesive coated tape when being drawn between the two rollers is angled at between 30 and 60xc2x0 to the carrier plate.
Preferably the tape collector roller is located downstream of the freely rotatable roller. The tape collector roller may be located generally under the freely rotatable roller. The tape collector roller may be located such that the adhesive coated tape when passing from the freely rotatable roller to the tape collector roller is angled at between 90xc2x0 and 330xc2x0 to the tape located between the driven and freely rotatable rollers.
The tape collector roller and the driven roller in the depressing station may be driven by a common drive means. The central driven rotatable member of the tape collector roller may be connected by drive means such as a chain, belt, etc., to the driven roller in the depressing station.
The backing layer removal station may be located in the region of the freely rotatable roller. The backing layer removal station may include means for guiding the blister pack away from the tape towards a tablet collection container. The tablet collection container may include a receptacle provided with an opening through which individual tablets may pass. Preferably the opening is sized/positioned such that the blister pack does not pass therethrough in normal use.
The apparatus may further include a receptacle for collecting empty blister packs, located adjacent to the tablet collection receptacle. The receptacle may include an opening through which the blister pack may pass.
According to the invention there is further provided a method for removing tablets from a blister pack including a formation for receiving the tablets and a backing layer which seals the formation and is rupturable to allow removal of the tablets, the method including the steps of bringing at least a part of the backing layer of the blister pack into contact with a flexible adhesive member and depressing the formation to rupture the backing layer sealing the formation, when the backing layer sealing the formation is in contact with the flexible adhesive member.
The method may further include the step of separating the flexible adhesive member in contact with the ruptured backing layer from the associated formation, a part of the ruptured backing layer remaining in contact with the flexible adhesive member and thereby releasing the tablet.
The flexible adhesive member may include an adhesive coated tape and the method may include the step of conveying the blister pack on the tape between a depressing station where the formation is depressed to rupture the backing layer and a backing layer removal station where a part of the ruptured backing layer is removed from the blister pack.
Means may be provided for drawing the adhesive coated tape through the depressing station and the backing layer removal station. The adhesive coated tape may be drawn over a carrier plate having a substantially planar upper face, the tape passing over the carrier plate with its adhesive coated face oriented away from the plate such that a blister pack located on the carrier plate is received on the adhesive coated face of the tape.
The method may include the step of conveying the blister pack on the adhesive coated tape from the carrier plate to the depressing station. The method may include the step of gripping an edge of the blister pack in the depressing station. The method may include the step of using a driven roller to grip an edge of the blister pack. The method may further include the step of using the driven roller to depress the formation to rupture the backing layer.
The method may further include the step of drawing the blister pack on the adhesive coated tape to the backing layer removal station, where the blister pack is guided away from the adhesive coated tape towards a tablet collection receptacle.